1. Field of the Invention
The present invention relates to a process for the removal of SO.sub.2 from two or more gas streams.
2. Description of the Prior Art
It is known to remove SO.sub.2 gas from a gas stream by absorbing the SO.sub.2 in a suitable absorbent. Examples of some prior art patents showing such a technique are: U.S. Pat. Nos. 2,563,437 and 3,047,364.
In certain situations, two or more gas streams containing differing SO.sub.2 levels will require treatment to remove the SO.sub.2 from each stream. It has been commonplace to combine such gas streams into a single stream prior to contact with the absorbent. In order to recover the SO.sub.2 values from such a resulting stream, large quantities of absorbent solution must be circulated due to the limitations of SO.sub.2 equilibrium solubility. Hence, a need exists for a more efficient way to absorb SO.sub.2 from two or more gas streams which contain varying SO.sub.2 levels.
In U.S. Pat. No. 4,123,507 to R. H. Hass two SO.sub.2 streams, presumably of differing SO.sub.2 content, are not combined and are supplied to an absorber at two differing points. This patent, however, fails to indicate the degree of difference of the SO.sub.2 content of the streams, fails to indicate which stream is the more concentrated, and fails to indicate any advantage for not combining the gas streams into a single stream prior to contact with the absorber. The patent illustrates recirculation of SO.sub.2 -rich absorbent through the absorber which would tend to equalize the concentration of SO.sub.2 gas in the absorber.